CN107301940B

CN107301940B - Method for analyzing an object and charged particle beam device for carrying out the method

Info

Publication number: CN107301940B
Application number: CN201611028040.2A
Authority: CN
Inventors: S.巴蒂普罗鲁; E.希尔
Original assignee: Carl Zeiss Microscopy GmbH; Carl Zeiss X Ray Microscopy Inc
Current assignee: Carl Zeiss Microscopy GmbH; Carl Zeiss X Ray Microscopy Inc
Priority date: 2015-11-19
Filing date: 2016-11-18
Publication date: 2020-08-25
Anticipated expiration: 2036-11-18
Also published as: US9620331B1; CN107301940A

Abstract

The present invention relates to a method for analyzing an object using a charged particle beam device generating a charged particle beam. Furthermore, the invention relates to a charged particle beam device for carrying out such a method. The method includes segmenting a portion of a volume element surface of an image of the object corresponding to a volume element into regions having a first color level and a second color level and determining respective region scores. The method includes the step of identifying a plurality of particles having respective color levels by comparing the color levels to information stored in a database. By comparing the color levels, possible particles, e.g. minerals, which may be included in the volume element may be identified.

Description

Method for analyzing an object and charged particle beam device for carrying out the method

Technical Field

The present invention relates to a method for analyzing an object using a charged particle beam device generating a charged particle beam. Furthermore, the invention relates to a charged particle beam device for carrying out such a method. In particular, the charged particle beam device is an electron beam device and/or an ion beam device.

Background

Charged particle beam devices are used for analyzing and examining objects (hereinafter also referred to as samples) in order to obtain insight into the behavior and behavior of the object under specific conditions. One of these charged particle beam devices is an electron beam device, in particular a scanning electron microscope (also referred to as SEM).

In an SEM, an electron beam (hereinafter also referred to as primary electron beam) is generated using a beam generator. The electrons of the primary electron beam are accelerated to a predetermined energy and focused by a beam guidance system, in particular an objective lens, onto a sample to be analyzed, i.e. an object to be analyzed. A high voltage source with a predeterminable acceleration voltage is used for acceleration purposes. Using a deflection unit, a primary electron beam is directed over the surface of the sample to be analyzed in a raster-like manner. In this case, the electrons of the primary electron beam interact with the material of the sample to be analyzed. In particular, interacting particles and/or interacting radiation occur as a result of the interaction. For example, electrons are emitted by the sample to be analyzed (so-called secondary electrons), and the electrons of the primary electron beam are backscattered at the sample to be analyzed (so-called backscattered electrons). Secondary and backscattered electrons are detected and used for image generation. Thus obtaining an image of the sample to be analyzed.

The interaction radiation comprises X-rays and/or cathode ray light and may be detected with a radiation detector. In the measurement of X-rays with a radiation detector, energy dispersive X-ray spectroscopy (also referred to as EDS or EDX) may be performed in particular. EDX is an analytical method for elemental analysis or chemical characterization.

Ion beam devices are also known from the prior art. The ion beam apparatus includes an ion beam column having an ion beam generator. Ions are generated for processing a sample (e.g., for removing a layer of the sample or for depositing material in the sample, wherein the material is provided by a gas injection system) or for imaging.

Furthermore, it is known from the prior art to use combination devices for processing and/or for analyzing samples, wherein both electrons and ions can be directed onto the sample to be processed and/or analyzed. For example, known SEMs are additionally equipped with an ion beam column as described above. SEM is used in particular for observing the treatment, but also for further analysis of treated or untreated samples. Electrons can also be used to deposit materials. This is called Electron Beam Induced Deposition (EBID).

EDX is generally used as an analytical analysis method for analyzing rocks in the field of mineralogy. It is possible to identify the composition of mineral particles, which is important information, in particular for lithologists who need to accurately determine the mineralogical properties of the rock. EDX typically requires irradiating the sample with electrons of an SEM having a landing energy of at least 15 keV. The landing energy is the energy that the electrons have when they impact on the sample. Electrons having such an energy penetrate rather deeply into the sample and generate X-rays from a volume element of the sample comprising an extension of about 2 μm in the first direction, in the second direction and in the third direction. Thus, the volume element comprises dimensions of about 2 μm × 2 μm × 2 μm. Correspondingly, the volume element also comprises a volume element surface of 2 μm × 2 μm. The volume element surface is also called EDX pixel.

Most mudstones to be analyzed comprise mineral particles smaller than 2 μm. Therefore, they are smaller than EDX pixels. Accordingly, the EDX spectrum generated based on X-rays emitted from the volume element may comprise not only information about a single mineral particle of interest, but also information about further surrounding mineral particles located in the volume element. Thus, the information provided by EDX spectroscopy may not be understood or may lead to erroneous results.

It is desirable to provide a method for analyzing an object using a charged particle beam device and a charged particle beam device for performing the method, which make it possible for a lithologist to accurately determine the mineralogical properties of the rock.

Disclosure of Invention

According to the invention, this is solved by a method according to claim 1. A further method according to the invention is given by claim 12. The features of claim 22 provide a computer program product comprising program code for controlling a charged particle beam device. A charged particle beam device for performing the method is given in claim 23. Additional features of the invention will become apparent from the following description, the following claims, and/or the accompanying drawings.

The method according to the invention is used for analyzing an object using a charged particle beam device (e.g. an electron beam device and/or an ion beam device). The charged particle beam device may comprise a charged particle generator for generating a charged particle beam with charged particles and an objective lens for focusing the charged particle beam onto the object. The charged particles may be electrons and/or ions. Furthermore, the charged particle beam device may comprise a first detection unit for detecting interacting particles and a second detection unit for detecting interacting radiation, the interacting particles and the interacting radiation being generated when the charged particle beam impinges on the object. The interacting particles may be secondary particles (e.g. secondary electrons) or backscattered particles (e.g. backscattered electrons). The interaction radiation may be X-ray or cathodo-ray light. Further, the charged particle beam device may comprise a database storing information about the characteristics of the first particles and the second particles. The first particles and/or the second particles may be minerals. The database includes the properties of these minerals, in particular their chemical composition. The database may include characteristics of more than the two types of particles described above. In a preferred embodiment, the database may include characteristics of several minerals from real samples originating from different regions of the world.

The method according to the invention comprises the steps of directing a charged particle beam over the object and detecting the interacting particles using the first detection unit. A first detection signal is generated using a first detection unit, and an image of the object is generated using the first detection signal. The image comprises regions with different color levels, e.g. different grey levels. Furthermore, the image has an image resolution that may be less than 100 nm.

The method further comprises the step of detecting the interacting radiation with a second detection unit. As mentioned above, the interacting radiation may be X-rays or cathodo-ray light. A second detection signal is generated using a second detection unit, and a radiation spectrum is generated using the second detection signal. The radiation spectrum includes, for example, signal intensity as a function of X-ray energy. Radiation spectroscopy can be used for EDX.

The radiance spectrum represents the volume element of the object and provides information about the overall material composition of the volume element. The volume element has a first extension along a first axis, a second extension along a second axis, and a third extension along a third axis. The first axis, the second axis and the third axis may be arranged perpendicular to each other. The first extension, the second extension and/or the third extension may be 2 μm. However, the first extension, the second extension and/or the third extension are not limited to this value. Rather, any suitable value may be selected. Further, the volume element has a volume element surface that is spanned by two of: a first axis, a second axis, and a third axis.

The graphics resolution is less than at least one of: a first extension, a second extension, and a third extension. According to one embodiment of the invention the image resolution is 100nm and the first extension, the second extension and/or the third extension is 2 μm.

The method according to the invention further comprises the steps of: a portion of the image corresponding to the volume unit surface is segmented into regions having a first color level and a second color level. In other words, the image generated using interacting particles and having a high resolution is segmented in the area of the volume element and in the volume element surface, respectively, in such a way that the first segment comprises an area having a first color level and the second segment comprises an area having a second color level. The first color level and/or the second color level may be a gray scale level.

The method according to the invention further comprises the steps of: a first area fraction of the area of the volume unit surface comprising a first color level and a second area fraction of the area of the volume unit surface comprising a second color level are determined. For example, a first fractional region of the region comprising a first color level is 70% of the area of the volume unit surface, and a second fractional region of the region comprising a second color level is 30% of the area of the volume unit surface.

The method according to the invention further comprises the steps of: first particles associated with the first color level are identified by comparing the first color level to information stored in a database and second particles associated with the second color level are identified by comparing the second color level to information stored in the database. In other words, the database is a look-up table comprising information about the first particle and the second particle. The information further comprises a first color level that the first particles typically have in an image generated using the interacting particles. The information further comprises a second color level that the second particles typically have in an image generated using the interacting particles. Thus, by comparing the color levels, possible particles (e.g., minerals) that may be included in a volume element may be identified.

The method according to the invention further comprises the steps of: determining a composition of a volume unit by using the information about the identified first particles (i.e., the characteristics of the identified first particles), the first region fraction, the information about the second particles (i.e., the characteristics of the identified second particles), and the second region fraction, wherein the composition of the volume unit consists of the first particles in an amount of the first region fraction in proportion to the second particles in an amount of the second region fraction. In other words, the proportion of the first particles in the composition of the volume element is equal to the proportion of the first region fraction in the entire area of the surface of the volume element. Further, the proportion of the second particles in the composition of the volume unit is equal to the proportion of the second region fraction in the entire area of the volume unit surface.

The method according to the invention makes it possible for the petrologist to determine the mineralogy of the rock accurately. The method combines the high resolution of images provided by a charged particle beam device with information provided by radiation analysis (e.g., EDX).

In addition or alternatively to the embodiments of the invention, provision is made for: at least one of the first color level and the second color level is a gray scale level, as already described above.

Furthermore, in addition or alternatively to the embodiments of the invention, provision is made for: at least one of the first particles and the second particles is a mineral.

Furthermore, in addition or alternatively to the embodiments of the invention, provision is made for: three color levels, in particular three grey levels, are determined in said part of the image of the volume element surface during the segmentation step. In particular, the database also stores information about the characteristics of the third particles. The region also includes a third color level. The method further comprises the steps of: determining a third region score of the region comprising a third color level and identifying the third particles associated with the third color level by comparing the third color level to the information stored in the database. Further, a composition of the volume unit is determined by using the information on the third particles and the fraction of the third region, wherein the composition of the volume unit is further proportionally composed of the fraction number of the third particles of the third region. In other words, the proportion of the third particles in the composition of the volume element is equal to the proportion of the third region fraction in the entire area of the volume element surface.

In addition or alternatively to the embodiments of the invention, provision is made for: the region of the portion of the image corresponding to the volume element surface comprises only the first, second and third color levels. Therefore, only up to three color levels are considered in the present embodiment. However, the present invention is not limited to the use of up to three color levels. Rather, any suitable number of color levels may be selected, for example, 5 to 20 color levels.

In addition or alternatively to the embodiments of the invention, provision is made for: the database comprises information on the characteristics of the plurality of particles, i.e. on the characteristics of the plurality of first particles and on the characteristics of the plurality of second particles. Further, the step of identifying the first particle may comprise: a portion or all of the plurality of first particles associated with a first color level is identified. In other words, all or a portion of the plurality of first particles associated with the first color level are identified by comparing the first color level to information stored in the database. The present embodiment of the invention is based on the following idea. As mentioned above, the database may include characteristics of several minerals, in particular their chemical composition. However, since several minerals differ only slightly from each other, they may have the same color level (e.g., grey scale) in an image generated using interacting particles. Thus, the database may comprise identical colour grades for different particles in mineral form. If the color grade obtained in the image of the object is associated with several particles in the form of minerals, the database will provide all the minerals associated with this obtained color grade. It is therefore desirable to identify the first particles actually included in the volume element from the number of possible first particles. Embodiments of the present invention identify a plurality of first particles by comparing a characteristic of each of some or all of the first particles to information about the overall material composition of the volume element. The first particles are selected whose properties are closest to the information about the overall material composition of the volume element. In other words, a single first particle is determined from part or all of the plurality of first particles in such a way that the characteristic of said single first particle is closest to the information on the overall material composition of the volume element relative to all of the plurality of first particles. Thus, a single first particle is selected from part or all of the plurality of first particles. The characteristic of this single first particle is closest to the overall material composition of the volume element provided by the radiation spectrum compared to any other characteristic of a further first particle of the plurality of first particles. The step of determining the composition of the volume unit now comprises: a single first particle is used.

Alternatively or additionally, the step of identifying second particles may comprise: identifying a portion or all of the plurality of second particles associated with a second color level. In other words, all or a portion of the plurality of second particles associated with the second color level are identified by comparing the second color level to information stored in the database. The present embodiment of the invention is based on exactly the same idea as described above. The database may comprise identical colour grades for different particles in mineral form. If the color grade obtained in the image of the object is associated with several particles in the form of minerals, the database will provide all the minerals associated with this obtained color grade. Therefore, it is desirable to also identify the second particles actually included in the volume unit from the number of possible second particles. Embodiments of the present invention identify a plurality of second particles by comparing a characteristic of each of the second particles of part or all of the second particles to information about the overall material composition of the volume element. Selecting a second particle having a property closest to the information on the overall material composition of the volume element. In other words, a single second particle is determined from part or all of the plurality of second particles such that the characteristic of the single second particle is closest to the information about the overall material composition of the volume element relative to all of the plurality of second particles. Thus, a single second particle is selected from part or all of the plurality of second particles. The characteristic of this single second particle is closest to the overall material composition of the volume element provided by the radiation spectrum compared to any other characteristic of a further second particle of the plurality of second particles. The step of determining the composition of the volume unit now comprises: a single second particle is used.

In addition or alternatively to the embodiments of the invention, provision is made for: segmenting the portion of the image corresponding to the surface of the volume element includes using a gray level histogram. A grayscale histogram of an image is a histogram of pixel intensity values of pixels in the image (i.e., the image generated using interacting particles). The histogram includes a count of pixels having a particular gray level intensity. Typically, the histogram shows a high distribution of pixels in the form of peaks. If two peaks are shown in the histogram, the two peaks are identified as a first color level and a second color level. If more than two peaks are identified, only the strongest two peaks (two colors) or three peaks (three colors) are selected.

In addition or alternatively, in a further embodiment of the invention, provision is made for: the first particles are identified by using the radiation spectrum only if they are larger than the surface of the volume element. Thus, the first particles are large particles, so that the above-mentioned problems of a volume unit comprising more than two particles do not occur. The radiation spectrum is generated by directing a charged particle beam to the center of a first particle (i.e., a large particle). The same applies to the second particles if they are larger than the volume unit surface.

Furthermore, in addition or alternatively to the embodiments of the invention, provision is made for: if the volume element comprises an organic material, a given chemical composition is specified for the organic material, for example a given chemical composition of 95% by weight of carbon (C) or 5% by weight of oxygen (O). Such a composition of organic materials is very common and accurate.

In addition or alternatively to the embodiments of the invention, provision is made for: the first detection unit and/or the second detection unit are calibrated using a calibration object. The present embodiment is based on the following idea. The database stores information about the characteristics of the mineral. The database is a look-up table that includes this information. In particular, the database includes characteristics of minerals from real samples originating from different regions of the world. Information about the particles/minerals is obtained once and stored in a database. In particular, the information includes the colour levels each mineral normally has in an image generated using interacting particles in a charged particle beam apparatus. Such a colour level may be determined by preliminary analysis of these minerals in a charged particle beam apparatus, using interacting particles (such as secondary and/or backscattered electrons) to generate an image. However, the color level depends on the mode of operation of the charged particle beam device. The mode of operation is particularly influenced by the landing energy of the charged particles on the object, the detector efficiency and the amplification of the detection signal. Accordingly, each analysis of an object with unknown composition may be performed using exactly the same mode of operation. This is provided by calibrating the first detection unit and/or the second detection unit using the calibration object. Furthermore, exactly the same landing energy may be used. The calibration of the first and/or second detection unit can be performed twice, the first time by means of a charged particle beam device for collecting information for the database and the second time by means of a charged particle beam device for performing the method according to the invention. The two charged particle beam devices may be different.

Another method according to the invention is also used for analyzing objects. Another approach also uses charged particle beam devices (e.g., electron beam devices and/or ion beam devices). The charged particle beam device may comprise a charged particle generator for generating a charged particle beam with charged particles and an objective lens for focusing the charged particle beam onto the object. The charged particles may be electrons and/or ions. Furthermore, the charged particle beam device may comprise a first detection unit for detecting interacting particles and a second detection unit for detecting interacting radiation, the interacting particles and the interacting radiation being generated when the charged particle beam impinges on the object. The interacting particles may be secondary particles (e.g. secondary electrons) or backscattered particles (e.g. backscattered electrons). The interaction radiation may be X-ray or cathodo-ray light. Further, the charged particle beam device may comprise a database storing information about the characteristics of the plurality of particles. The particles may be minerals. The database includes the properties of these minerals, in particular their chemical composition. In a preferred embodiment, the database may include characteristics of several minerals from real samples originating from different regions of the world.

Another method according to the invention comprises the steps of directing a charged particle beam over the object and detecting the interacting particles using a first detection unit. A first detection signal is generated using a first detection unit, and an image of the object is generated using the first detection signal. The image comprises regions with different color levels, e.g. different grey levels. Furthermore, the image has an image resolution that may be less than 100 nm.

Another method further comprises the step of detecting the interacting radiation with a second detection unit. As mentioned above, the interacting radiation may be X-rays or cathodo-ray light. A second detection signal is generated using a second detection unit, and a radiation spectrum is generated using the second detection signal. The radiation spectrum includes, for example, signal intensity as a function of X-ray energy. Radiation spectroscopy can be used for EDX.

The radiance spectrum represents the volume element of the object and provides information about the overall composition of the volume element. The volume element has a first extension along a first axis, a second extension along a second axis, and a third extension along a third axis. The first axis, the second axis and the third axis may be arranged perpendicular to each other. The first extension, the second extension and/or the third extension may be 2 μm. However, the first extension, the second extension and/or the third extension are not limited to this value. Rather, any suitable value may be selected. Further, the volume element has a volume element surface that is spanned by two of: a first axis, a second axis, and a third axis.

The graphics resolution is less than at least one of: a first extension, a second extension, and a third extension. According to one embodiment of the invention the image resolution is 100nm and the first extension, the second extension and/or the third extension is 2 μm. The image resolution may also be less than 100nm, in particular 50nm or less, 10nm or less or 5nm or less.

Another method according to the invention further comprises the steps of: a portion of an image corresponding to a surface of a volume element is segmented into regions having a first color level and a second color level. In other words, the image generated using interacting particles and having a high resolution is segmented in the area of the volume element and in the volume element surface, respectively, in such a way that the first segment comprises an area having a first color level and the second segment comprises an area having a second color level. The first color level and/or the second color level may be a gray scale level.

Another method according to the invention further comprises the steps of: a first region score of the region comprising a first color level is determined and a second region score of the region comprising a second color level is determined. For example, a first fractional region of the region comprising a first color level is 70% of the area of the volume unit surface, and a second fractional region of the region comprising a second color level is 30% of the area of the volume unit surface.

Another method according to the invention further comprises the steps of: a first portion of the plurality of particles is identified by comparing the first color level to information stored in the database, the first portion being associated with the first color level, and a second portion of the plurality of particles is identified by comparing the second color level to information stored in the database, the second portion being associated with the second color level. In other words, the database is a look-up table that includes information about the particles. The information also includes the color levels that the particles typically have in an image generated using interacting particles. Thus, by comparing the color levels, possible particles (e.g., minerals) that may be included in a volume element may be identified. A first portion of the plurality of particles is assigned possible particles having a first color level. A second portion of the plurality of particles is assigned possible particles having a second color level.

Another method according to the invention further comprises the steps of: determining a possible composition of the volume unit for each possible combination of the individual particles of the first portion of the plurality of particles and the individual particles of the second portion of the plurality of particles by using the characteristics of each individual particle of the first portion of the plurality of particles, the first region fraction, the characteristics of each individual particle of the second portion of the plurality of particles, and the second region fraction, wherein the composition of the volume unit consists of the individual particles of the first portion of the plurality of particles in an amount of the first region fraction in proportion to the individual particles of the second portion of the plurality of particles in an amount of the second region fraction.

Another method according to the invention further comprises the steps of: comparing each possible composition to the overall material composition of the volume element provided by the radiation spectrum; and determining the actual composition of the volume element by selecting the composition from the possible compositions that is closest to the overall material composition of the volume element provided by the radiation spectrum.

Another method according to the invention has the same advantages as described above in relation to the other methods according to the invention.

In addition or alternatively to the embodiment of the method according to the invention, provision is made for: at least one of the first color level and the second color level is a gray scale level, as already described above. In addition or alternatively, in an embodiment of a further method according to the invention, it is provided that: the particles are minerals.

In addition or alternatively, in an embodiment of a further method according to the invention, it is provided that: three color levels, in particular three grey levels, are determined in the part of the image corresponding to the surface of the volume element during the segmentation step. In particular, the database also stores information about the characteristics of the third particles. The region of the portion of the image corresponding to the volume element surface further comprises a third color level. The method further comprises the step of determining a third region score of said region comprising a third color level. Further, an embodiment comprises the steps of: a third portion of the plurality of particles is identified by comparing the third color level to information stored in the database, the third portion associated with the third color level. The step of determining the possible composition of the volume element also takes into account each possible combination with each individual particle of the third portion of the plurality of particles by using the characteristics of the individual particles of the third portion of the plurality of particles and the third region fraction.

In addition or alternatively to the embodiment of the method according to the invention, provision is made for: the region of the image corresponding to a portion of the volume element surface includes only the first color level, the second color level, and the third color level. Therefore, only up to three color levels are considered. However, the present invention is not limited to the present embodiment. Rather, any suitable number of color levels may be selected, e.g., 4 to 20.

In addition or alternatively to the embodiment of the method according to the invention, provision is made for: segmenting the portion of the image corresponding to the surface of the volume element comprises using a grey level histogram as already described above.

In addition or alternatively to a further exemplary embodiment of a further method according to the invention, provision is made for: the particle is identified by using the radiation spectrum only if the volume element comprises only this particle and if the particle is larger than the volume element. Thus, the particles are large particles, so that the above-mentioned problems of a volume unit comprising more than two particles do not occur. The radiation spectrum is generated by directing a charged particle beam to the center of a first particle (i.e., a large particle).

In addition or alternatively, in an embodiment of a further method according to the invention, it is provided that: if the volume element comprises an organic material, a given chemical composition is specified for the organic material, for example a given chemical composition of 95% by weight of carbon (C) or 5% by weight of oxygen (O). Such a composition of organic materials is very common and accurate.

In addition or alternatively to the embodiment of the method according to the invention, provision is made for: the first detection unit and/or the second detection unit are calibrated using a calibration object. The present embodiment is based on the concept as has been described above.

The invention also relates to a computer program product comprising program code, which is loadable or loaded into a processor and which, when executed, controls a charged particle beam device in such a way that a method comprising at least one of the steps described above or further below or a combination of at least two of the steps described above or further below is performed.

The method also relates to a charged particle beam device for analyzing an object. The charged particle beam device comprises at least one charged particle generator for generating a charged particle beam comprising charged particles. The charged particles may be electrons and/or ions. The charged particle beam device also has at least one objective lens for focusing the charged particle beam onto the object. Furthermore, the charged particle beam device comprises at least one first detection unit for detecting the interacting particles and at least one second detection unit for detecting the interacting radiation, the interacting particles and the interacting radiation being generated when the charged particle beam impinges on the object. The interacting particles may be secondary and/or backscattered particles, in particular secondary and backscattered electrons. The interaction radiation may be X-rays and/or cathodo-ray light. Further, the charged particle beam device comprises a database storing information about the characteristics of the particles (e.g. the first particles and the second particles). As mentioned above, the particles may be minerals. The database includes the properties of these minerals, in particular their chemical composition. The database may include characteristics of more than the two types of particles described above. In a preferred embodiment, the database comprises characteristics of several minerals from real samples originating from different regions of the world. Furthermore, the charged particle beam device comprises at least one processor into which the computer program product as described above is loaded.

In an embodiment of the charged particle beam device according to the invention, it is additionally or alternatively provided that the first detector comprises a first detection unit and the second detector comprises a second detection unit. Thus, the two detector units are arranged in different detectors. In an alternative embodiment, the single detector comprises a first detection unit and a second detection unit.

In an embodiment of the charged particle beam device according to the invention, it is additionally or alternatively provided that the charged particle generator is a first charged particle generator for generating a first charged particle beam comprising first charged particles. The objective lens is a first objective lens for focusing the first charged particle beam onto the object. The charged particle beam device further comprises a second charged particle beam generator for generating a second charged particle beam comprising second charged particles and a second objective lens for focusing the second charged particle beam onto the object.

In an embodiment of the charged particle beam device according to the invention, the additionally or alternatively provided charged particle beam device is at least one of: an electron beam device or an ion beam device. In particular, the charged particle beam device may be both an electron beam device and an ion beam device.

The present invention also relates to another method for solving the above-mentioned problems of the prior art. Another approach is based on the fact that high resolution is desired for most digital imaging applications. One possible solution to increase the spatial resolution is to reduce the size of the pixels in the image. However, this is not a viable solution for applications where the resolution is dictated by an object having an interaction volume (such as the object discussed further above). The invention is therefore also based on the idea of using signal processing techniques to reconstruct a high resolution image from an original low resolution image. This is performed by oversampling the image in order to reconstruct a higher Resolution image, which is disclosed in Carmi et al, "Resolution enhancement in MRI," Magnetic Resonance Imaging 24, (2006) pages 133 to 154.

Drawings

Embodiments of the invention described herein are explained in more detail below with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic view of a first embodiment of a charged particle beam device;

FIG. 1A shows a schematic view of a second embodiment of a charged particle beam device;

FIG. 2 shows a schematic view of a third embodiment of a charged particle beam device;

FIG. 3 shows a schematic view of a fourth embodiment of a charged particle beam device;

FIG. 4 shows a further schematic view of the charged particle beam device according to FIG. 3;

FIG. 5 shows a flow diagram of an embodiment of a method of obtaining a property of a mineral;

FIG. 6 shows a flow diagram of an embodiment of a method of calibrating a charged particle beam device and preparing an object to be analyzed;

FIG. 7 shows a flow chart of an embodiment of a method according to the invention;

FIG. 7A shows a further flow chart of an embodiment of a method according to the invention;

FIG. 8 shows an image of an object, wherein the image is generated using a charged particle beam device;

fig. 9 shows the radiation spectrum of an object, wherein the radiation spectrum is used for performing EDX;

FIG. 10 shows a volume element of an object to be analyzed;

FIG. 11 shows several volume elements of an object to be analyzed;

FIG. 12 shows a schematic diagram of a gray level histogram including peaks; and

fig. 13 shows a schematic view of a segmented part of an image of an object to be analyzed.

Detailed Description

Fig. 1 shows a schematic view of SEM 100. The SEM100 has a beam generator in the form of an electron source 101 as a cathode, an extraction electrode 102 and an anode 103, said anode 103 being arranged at one end of a beam guide tube 104 of the SEM 100. The electron source 101 is, for example, a thermal field emitter. However, the present invention is not limited to such an electron source. Rather, any electron source may be used.

The electrons emitted from the electron source 101 form a primary electron beam. The electrons are accelerated to the anode potential due to the potential difference between the electron source 101 and the anode 103. The anode potential in this exemplary embodiment is between 0.2kV and 30kV with respect to the ground potential of the object chamber 120, for example 5kV to 15kV, in particular 8kV, but alternatively it may also be ground potential.

Two condenser lenses are arranged at the beam guide pipe 104, i.e., a first condenser lens 105 and a second condenser lens 106, the first condenser lens 105 being located in front as viewed from the electron source 101 toward the objective lens 107, and then the second condenser lens 106. However, the present invention is not limited to the use of two condenser lenses. Rather, another embodiment may include only a single condenser lens.

The first diaphragm unit 108 is arranged between the anode 103 and the first condenser lens 105. The first aperture unit 108 is at a high voltage potential, i.e. the potential of the anode 103 or ground potential, together with the anode 103 and the beam guide tube 104. The first diaphragm unit 108 may have a plurality of first diaphragm apertures 108A. One of the first diaphragm openings 108A is shown in fig. 1. For example, the first diaphragm unit 108 has two first diaphragm openings 108A. Each of the plurality of first diaphragm openings 108A may have a different opening diameter. The selected first aperture opening 108A may be arranged at the optical axis OA of the SEM100 using an adaptation mechanism. However, the present invention is not limited to the present embodiment. Rather, in an alternative embodiment, the first diaphragm unit 108 may have only a single first diaphragm opening 108A. This alternative embodiment does not use an adapter mechanism. The first aperture unit 108 of this alternative embodiment is fixedly arranged around the optical axis OA.

The fixed second aperture unit 109 is arranged between the first condenser lens 105 and the second condenser lens 106. Alternatively, the second diaphragm unit 109 is movable.

The objective lens 107 has a pole piece 110 in which an aperture has been made. A beam guide tube 104 is arranged and guided through this aperture. Furthermore, a coil 111 is arranged in the pole piece 110.

An electrostatic deceleration device is located downstream of the beam guide tube 104. It has a single electrode 112 and a tubular electrode 113 arranged at the end of the beam guide tube 104 facing the object 114. Thus, the tubular electrode 113 together with the beam guide tube 104 is at the potential of the anode 103, whereas the single electrode 112 and the object 114 are at a lower potential than the anode 103. In this case, this is the ground potential of the object chamber 120. Thus, the electrons of the primary electron beam may be decelerated to a desired energy required to analyze the object 114.

Furthermore, SEM100 has a scanning device 115, via which scanning device 115 a primary electron beam may be deflected and scanned across object 114. In this process, the electrons of the primary electron beam interact with the object 114. As a result of this interaction, detected interacting particles and/or interacting radiation will be generated. The detection signal obtained in this way is evaluated.

As interacting particles, electrons are emitted from the surface of the object 114 (so-called secondary electrons) or electrons of the primary electron beam are backscattered (so-called backscattered electrons), in particular. For the detection of secondary and/or backscattered electrons a detector system with a first detector 116 and a second detector 117 is arranged in the beam guide tube 104. In the beam guide pipe 104, a first detector 116 is arranged on the source side along the optical axis OA, and a second detector 117 is arranged on the object side along the optical axis OA. Further, the first detector 116 and the second detector 117 are arranged to deviate from each other towards the optical axis OA of the SEM 100. Both the first detector 116 and the second detector 117 each have a through hole through which the primary electron beam can pass, and they are at approximately the potential of the anode 103 and the beam guide tube 104. The optical axis OA of the SEM100 passes through the corresponding through hole.

The second detector 117 is mainly used for detecting secondary electrons. The secondary electrons emitted from the object 114 have low kinetic energy and an arbitrary moving direction. However, the secondary electrons are accelerated due to the strong extraction field generated by the tubular electrode 113 in the direction of the objective lens 107. The secondary electrons enter the objective lens 107 almost parallel to the optical axis OA. The diameter of the beam bunch of secondary electrons is small in the objective lens 107. However, the objective lens 107 influences the beam of secondary electrons and generates a short focus of secondary electrons having a relatively steep angle with respect to the optical axis OA, so that the secondary electrons diverge from each other after focusing and may impinge on the second detector 117. Electrons backscattered on the object 114 (i.e., backscattered electrons) have a relatively higher kinetic energy when exiting from the object 114 as compared to secondary electrons. The backscattered electrons are detected only to a very small extent by the second detector 117. The high kinetic energy and the angle of the backscattered electron beam with respect to the optical axis OA when backscattered at the object 114 results in a beam waist of backscattered electrons, i.e. the beam area with the smallest diameter, which is arranged near the second detector 117. Therefore, a large portion of the backscattered electrons pass through the opening of the second detector 117. Accordingly, the backscattered electrons are mainly detected by the first detector 116.

The first detector 116 of another embodiment of SEM100 may have an inverted field grid 116A, which is a field grid having an opposite potential. The reverse field grid 116A may be arranged on a side of the first detector 116 facing the object 114. The reverse field grid 116A may comprise a negative potential relative to the potential of the beam guide tube 104 such that primarily or only backscattered electrons having high energy may pass through the reverse field grid 116A and impinge on the first detector 116. Additionally or alternatively, the second detector 117 may have another inverse field grid, which is similar in design and function to the inverse field grid 116A described above for the first detector 116.

The detection signals generated by the first detector 116 and the second detector 117 are used to generate an image of the surface of the object 114. It is explicitly noted that the diaphragm openings of the first diaphragm unit 108 and the second diaphragm unit 109 and the through holes of the first detector 116 and the second detector 117 are shown in an exaggerated manner. The through holes of the first and

second detectors

116, 117 have a maximum length perpendicular to the optical axis OA of between 1mm and 5 mm. For example, they have a circular design and have a diameter in the range of 1mm to 3mm perpendicular to the optical axis OA.

In the exemplary embodiment shown here, the second aperture unit 109 is a circular aperture having a second aperture opening 118 through which the primary electron beam passes, the second aperture opening 118 having an extension in the range of 25 μm to 50 μm, for example 35 μm. The second aperture unit 109 may be a pressure level aperture. The second aperture unit 109 of another exemplary embodiment may have several openings that are mechanically movable with respect to the primary electron beam or may be traversed by the primary electron beam using electrical and/or magnetic deflection means. As described above, the second aperture unit 109 may also be a pressure level unit. It will have an ultra-high vacuum (10)^-7To 10^- ¹²hPa) with a first area in which an electron source 101 is arranged and a high vacuum (10)^-3To 10^-7hPa) is separated. The second region is the intermediate pressure region of the beam guide tube 104 leading to the object chamber 120.

In addition to the detector systems described above, SEM100 has a radiation detector 500 arranged in object chamber 120. For example, the radiation detector 500 is positioned between the beam guide tube 104 and the object 114. Further, a radiation detector 500 is positioned on one side of the object 114. The radiation detector 500 may be a CCD detector.

The object chamber 120 operates in a first pressure range or a second pressure range, whereinThe first pressure range only including less than or equal to 10^-3A pressure of hPa, and wherein the second pressure range comprises only 10 or more^-3Pressure of hPa. A pressure sensor 600 is arranged in the object chamber 120 for measuring the pressure in the object chamber 120. A pump system 601 connected to the pressure sensor 600 and arranged at the object chamber 120 provides a pressure range, either the first pressure range or the second pressure range, in the object chamber 120.

SEM100 may further have a third detector 121 arranged in object chamber 120. The third detector 121 is arranged downstream of the object 114, as seen from the electron source 101 in the direction of the object 114 along the optical axis OA. The primary electron beam is transmittable through the object 114. The electrons of the primary electron beam interact with the material of the object 114. The electrons transmitted through the object 114 will be detected using the third detector 121.

The first detector 116, the second detector 117 and the radiation detector 500 are connected to a control unit 700. The control unit 700 comprises a processor 701 into which processor 701 a computer program product comprising program code is loaded, which program code, when executed, controls the SEM100 in such a way that the method according to the invention is performed. As will be further explained below.

Fig. 1A shows a schematic view of an additional SEM 100. The embodiment of fig. 1A is based on the embodiment of fig. 1. Identical reference numerals indicate identical components. In contrast to SEM100 of FIG. 1, SEM100 of FIG. 1A includes object chamber 122. The pressure limiting aperture 602 is arranged between the beam guide tube 104 and the object region 123 of the object chamber 122. SEM100 according to fig. 1A is particularly suited for SEM100 operating in a second pressure range.

Fig. 2 is a schematic view of another embodiment of a charged particle beam device according to the present invention. The present embodiment of the charged particle beam device is denoted by reference numeral 200 and comprises correction mirrors for correcting e.g. chromatic and spherical aberrations. This will be described in further detail below. The charged particle beam device 200 comprises a particle beam column 201 embodied as an electron beam column and corresponds in principle to the electron beam column of a corrected SEM. However, the charged particle beam device 200 according to the present invention is not limited to the SEM having a corrector mirror. Rather, any charged particle beam device including a correction unit may be used.

The particle beam column 201 comprises a beam generator in the form of an electron source 202 as a cathode, an extraction electrode 203 and an anode 204. The electron source 202 may be, for example, a thermal field emitter. The electrons emitted from the electron source 202 are accelerated by the anode 204 due to a potential difference between the electron source 202 and the anode 204. Accordingly, a primary particle beam in the form of an electron beam is provided along the first optical axis OA 1.

The primary particle beam is directed along a beam path (which is substantially the first optical axis OA1 after the primary particle beam has exited the electron source 202) using a first electrostatic lens 205, a second electrostatic lens 206 and a third electrostatic lens 207.

The primary particle beam is aligned along a beam path using at least one beam alignment device. The beam alignment apparatus of the present embodiment comprises a gun alignment unit comprising two magnetic deflection units 208 arranged along a first optical axis OA 1. Further, the particle beam device 200 includes an electrostatic beam deflection unit. The first electrostatic beam deflection unit 209 is arranged between the second electrostatic lens 206 and the third electrostatic lens 207. A first electrostatic beam deflection unit 209 is also arranged downstream of the magnetic deflection unit 208. A first multipole unit 209A in the form of a first magnetic deflection unit is arranged on one side of the first electrostatic beam deflection unit 209. Furthermore, a second multipole unit 209B in the form of a second magnetic deflection unit is arranged on the other side of the first electrostatic beam deflection unit 209. The first electrostatic beam deflection unit 209, the first multipole unit 209A and the second multipole unit 209B are used to adjust the primary particle beam with respect to the axis of the third electrostatic lens 207 and the entrance window of the beam deflection device 210. The first electrostatic beam deflection unit 209, the first multipole unit 209A and the second multipole unit 209B may together act as a Wien filter. A further magnetic deflection device 232 is arranged at the entrance of the beam deflection device 210.

The beam deflection device 210 acts as a particle-beam splitter, which deflects the primary particle beam in a specific manner. The beam deflecting means 210 comprises a number of magnetic sectors, namely a first magnetic sector 211A, a second magnetic sector 211B, a third magnetic sector 211C, a fourth magnetic sector 211D, a fifth magnetic sector 211E, a sixth magnetic sector 211F and a seventh magnetic sector 211G. The primary particle beam enters the beam deflection device 210 along a first optical axis OA1 and is deflected by the beam deflection device 210 in the direction of a second optical axis OA 2. The beam deflection is provided by a first magnetic sector 211A, a second magnetic sector 211B and a third magnetic sector 211C at an angle of 30 ° to 120 °. The second optical axis OA2 is arranged at exactly the same angle as the first optical axis OA 1. The beam deflection device 210 also deflects the primary particle beam directed along the second optical axis OA2 in the direction of the third optical axis OA 3. Beam deflection is provided by the third magnetic sector 211C, the fourth magnetic sector 211D, and the fifth magnetic sector 211E. In the embodiment shown in fig. 2, the deflection to the second optical axis OA2 and to the third optical axis OA3 will be done by deflecting the primary particle beam at an angle of 90 °. Accordingly, the third optical axis OA3 extends coaxially with the first optical axis OA 1. However, the charged particle beam device 200 according to the present invention is not limited to the 90 ° deflection angle. Rather, any suitable deflection angle (e.g., 70 ° or 110 °) may be used in conjunction with the beam deflection arrangement 210, such that the first optical axis OA1 does not extend coaxially with the third optical axis OA 3. For further details regarding the beam deflecting means 210, reference is made to WO 2002/067286A 2, which is hereby incorporated by reference.

After being deflected by the first, second and third

magnetic sectors

211A, 211B, 211C, the primary particle beam is directed along the second optical axis OA 2. The primary particle beam is directed to the electrostatic mirror 214 and on its way to the electrostatic mirror 214 passes through a fourth electrostatic lens 215, a third multipole unit in the form of a magnetic deflection unit 216A, a second electrostatic beam deflection unit 216, a third electrostatic beam deflection unit 217 and a fourth multipole unit in the form of a magnetic deflection unit 216B. The electrostatic mirror 214 includes a first mirror electrode 213A, a second mirror electrode 213B, and a third mirror electrode 213C. The electrons of the primary particle beam reflected back by the electrostatic mirror 214 travel along the second optical axis OA2 and re-enter the beam deflection means 210. They are deflected by the third magnetic sector 211C, the fourth magnetic sector 211D and the fifth magnetic sector 211E towards the third optical axis OA 3. The electrons of the primary particle beam leave the beam deflection device 210 and are directed along the third optical axis OA3 towards the object 225 to be examined. On its way to the object 225, the primary particle beam passes through the fifth electrostatic lens 218, the beam guide tube 220, the fifth multipole unit 218A, the sixth multipole unit 218B and the objective lens 221. The fifth electrostatic lens 218 is an electrostatic immersion lens. The primary particle beam is decelerated or accelerated by the fifth electrostatic lens 218 to the potential of the beam guide tube 220.

The primary particle beam is focused by the objective lens 221 in a focal plane in which the object 225 is located. The object 225 is arranged on the movable sample stage 224. The movable sample stage 224 is arranged in an object chamber 226 of the charged particle beam device 200.

The objective lens 221 may be implemented as a combination of the magnetic lens 222 and the sixth electrostatic lens 223. One end of the beam guide pipe 220 may be one electrode of the electrostatic lens. The particles of the primary particle beam are decelerated after exiting from the beam guide tube 220 to the potential of an object 225 arranged on a sample stage 224. The objective lens 221 is not limited to the combination of the magnetic lens 222 and the sixth electrostatic lens 223. Rather, the objective lens 221 may be implemented in any suitable form. Specifically, the objective lens 221 may also be only a simple magnetic lens or only a simple electrostatic lens.

The primary particle beam focused on the object 225 interacts with the object 225. Generating interacting particles and interacting radiation. Specifically, secondary electrons are emitted by the object 225, and backscattered electrons are returned from the object 225. The secondary and backscattered electrons are again accelerated and directed into the beam guide tube 220 along the third optical axis OA 3. In particular, the secondary electrons and the backscattered electrons travel on the beam path of the primary particle beam in opposite directions of the primary particle beam.

The charged particle beam device 200 comprises a first detector 219 arranged along the beam path between the beam deflection device 210 and the objective lens 221. Secondary electrons directed in directions oriented at large angles relative to the third optical axis OA3 are detected by the first detector 219. However, backscattered electrons and secondary electrons directed in a direction having a small axial distance with respect to the third optical axis OA3 at the first detector 219 (i.e. backscattered electrons and secondary electrons having a small distance to the third optical axis OA3 at the position of the first detector 219) enter the beam deflection means 210 and are deflected by the fifth, sixth and seventh

magnetic sectors

211E, 211F, 211G along the detection beam path 227 to the second detector 228 of the analysis unit 231. The total deflection angle may be, for example, 90 ° or 110 °.

The first detector 219 generates a detection signal mainly based on the emitted secondary electrons. The second detector 228 of the analysis unit 231 generates a detection signal mainly based on the backscattered electrons. The detection signals generated by the first detector 219 and the second detector 228 are transmitted to the control unit 700 and are used to obtain information about the properties of the area of interaction of the focused primary particle beam with the object 225. If the focused primary particle beam is scanned over the object 225 using the scanning device 229 and if the control unit 700 acquires and stores detection signals generated by the first detector 219 and the second detector 228, an image of the scanned area of the object 225 may be acquired and displayed by the control unit 700 or a monitor (not shown).

The filter electrode 230 may be arranged in front of the second detector 228 of the analysis unit 231. Filter electrode 230 may be used to separate secondary electrons from backscattered electrons due to the kinetic energy difference between the secondary electrons and backscattered electrons.

In addition to the first detector 219 and the second detector 228, the charged particle beam device 200 has a radiation detector 500 arranged in the object chamber 226. The radiation detector 500 is positioned on one side of the object 225 and directed at the object 225. The radiation detector 500 may be a CCD detector and detects interaction radiation, in particular X-rays and/or cathode ray light, resulting from the interaction of the primary particle beam with the object 225.

The object chamber 226 operates in a first pressure range or a second pressure range, wherein the first pressure range includes only less than or equal to 10^-3A pressure of hPa, and wherein the second pressure range comprises only 10 or more^-3Pressure of hPa. A pressure sensor 600 is arranged in the object chamber 226 for measuring the pressure in the object chamber 226. A pump system 601 connected to the pressure sensor 600 and arranged at the object chamber 226 provides a pressure range, a first pressure range or a second pressure range, in the object chamber 226And (5) enclosing.

The first detector 219, the second detector 228 of the analysis unit 231 and the radiation detector 500 are connected to a control unit 700. The control unit 700 comprises a processor 701 into which a computer program product comprising program code is loaded, which program code, when executed, controls the charged particle beam device 200 in such a way that the method according to the invention is performed. As will be further explained below.

Fig. 3 shows a schematic view of another embodiment of a charged particle beam device 300 according to the present invention. The charged particle beam device 300 has a first particle beam column 301 in the form of an ion beam column and a second particle beam column 302 in the form of an electron beam column. The first particle beam column 301 and the second particle beam column 302 are arranged on an object chamber 303 in which an object 304 to be analyzed and/or processed is arranged. It is explicitly noted that the system described herein is not limited to the first particle beam column 301 in the form of an ion beam column and the second particle beam column 302 in the form of an electron beam column. In practice, the system described herein also provides the first particle beam column 301 in the form of an electron beam column and the second particle beam column 302 in the form of an ion beam column. Another embodiment of the system described herein provides both the first particle beam column 301 and the second particle beam column 302 each in the form of an ion beam column.

Fig. 4 shows a detailed view of the charged particle beam device 300 shown in fig. 3. Object chamber 303 is not shown for clarity. A first particle beam column 301 in the form of an ion beam column has a first optical axis 305. Furthermore, a second particle beam column 302 in the form of an electron beam column has a second optical axis 306.

Next, the second particle beam column 302 in the form of an electron beam column will be described. The second particle beam column 302 has a second beam generator 307, a first electrode 308, a second electrode 309 and a third electrode 310. The second beam generator 307 is, for example, a thermal field generator. The first electrode 308 has a function as a suppressor electrode, and the second electrode 309 has a function as an extractor electrode. The third electrode 310 is an anode and simultaneously forms one end of the beam guide tube 311.

A second particle beam 312 in the form of an electron beam is generated by a second beam generator 307. The electrons emitted from the second beam generator 307 are accelerated to an anode potential, for example, in the range from 1kV to 30kV, due to a potential difference between the second beam generator 307 and the third electrode 310. A second particle beam 312 in the form of an electron beam passes through the beam guide tube 311 and is focused onto the object 304 to be analyzed and/or processed. This will be described in more detail further below.

The beam guide tube 311 passes through a collimator arrangement 313 having a first ring coil 314 and a deflection coil 315. Viewed in the direction of the object 304 from the second beam generator 307, the collimator arrangement 313 is followed by a pinhole diaphragm 316 and a detector 317, wherein a central opening 318 is arranged along the second optical axis 306 in the beam guide tube 311.

The beam guide tube 311 then extends through an aperture in the second objective lens 319. The second objective lens 319 is used to focus the second particle beam 312 onto the object 304. For this purpose, the second objective lens 319 has a magnetic lens 320 and an electrostatic lens 321. The magnetic lens 320 includes a second toroidal coil 322, an inner pole piece 323, and an outer pole piece 324. The electrostatic lens 321 includes one end 325 of the beam guide pipe 311 and a terminating electrode 326.

The one end 325 of the beam guide tube 311 and the terminating electrode 326 simultaneously form an electrostatic deceleration device. One end 325 of the beam guide tube 311 is at an anode potential with the beam guide tube 311, while the terminating electrode 326 and the object 304 are at a potential lower than the anode potential. This allows the electrons of the second particle beam 312 to be decelerated to a desired energy required for inspecting the object 304.

The second particle beam column 302 furthermore has a raster device 327, by means of which raster device 327 the second particle beam 312 can be deflected and scanned over the object 304 in raster form.

For imaging purposes, a detector 317 arranged in the beam guide tube 311 detects secondary and/or backscattered electrons generated by the interaction between the second particle beam 312 and the object 304. The signal generated by the detector 317 is transmitted to the control unit 700.

The interacting radiation (e.g. X-rays or cathodo-light) may be detected by using a radiation detector 500 (e.g. a CCD detector), said radiation detector 500 being arranged in the object chamber 303 (see fig. 3). The radiation detector 500 is positioned on one side of the object 304 and directed at the object 304.

The object 304 is arranged on an object holder 328 in the form of a sample stage as shown in fig. 3, the object 304 being arranged by said object holder 328 such that it is movable along three axes arranged perpendicular to each other, in particular the x-axis, the y-axis and the z-axis. Further, the sample stage is rotatable about two rotation axes arranged perpendicular to each other. The object 304 may thus be moved to a desired position. Rotation of object holder 328 about one of two axes of rotation may be used to tilt object holder 328 such that the surface of object 304 may be oriented perpendicular to second particle beam 312 or first particle beam 329, as described further below. Alternatively, the surface of object 304 may be oriented in such a way that the surface of object 304 on the one hand and first particle beam 329 or second particle beam 312 on the other hand are at an angle in the range of, for example, 0 ° to 90 °.

As described above, reference numeral 301 denotes a first particle beam column in the form of an ion beam column. The first particle beam column 301 has a first beam generator 330 in the form of an ion source. The first beam generator 330 is for generating a first particle beam 329 in the form of an ion beam. The first particle beam column 301 includes an extraction electrode 331 and a collimator 332. In the direction of the object 304 along the first optical axis 305, the collimator 332 is followed by an iris diaphragm 333. The first particle beam 329 is focused onto the object 304 by a first objective lens 334 in the form of a focusing lens. A photo gate electrode 335 is provided to scan a first particle beam 329 over object 304 in a raster fashion.

When the first particle beam 329 impacts the object 304, the first particle beam 329 interacts with the material of the object 304. In the process, interacting radiation is generated and detected using radiation detector 500. Interacting particles, in particular secondary electrons and/or secondary ions, are generated. These are detected using detector 317.

The object chamber 303 operates in a first pressure range or a second pressure range, wherein the first pressure range comprises only less than or equal to 10^-3A pressure of hPa, and wherein the second pressure range comprises only pressures equal to or higherAt 10^-3Pressure of hPa. A pressure sensor 600 is arranged in the object chamber 303 for measuring the pressure in the object chamber 303 (see fig. 3). A pump system 601 connected to the pressure sensor 600 and arranged at the object chamber 303 provides a pressure range, either the first pressure range or the second pressure range, in the object chamber 303.

First particle beam 329 may also be used to process object 304. For example, a first particle beam 329 may be used to deposit material on a surface of object 304, where the material is provided using a Gas Injection System (GIS). Additionally or alternatively, structures may be etched into object 304 using first particle beam 329. Furthermore, the second particle beam 312 may be used for treating the object 304, for example by electron beam induced deposition.

The detector 317 and the radiation detector 500 are connected to a control unit 700, as shown in fig. 3 and 4. The control unit 700 comprises a processor 701 into which a computer program product comprising program code is loaded, which program code, when executed, controls the charged particle beam device 300 in such a way that the method according to the invention is performed. As will be further explained below.

An embodiment of the method according to the invention, which is performed using SEM100 according to fig. 1, will now be described. Note that the method can also be performed with other charged particle beam devices (specifically SEM100 of fig. 1A, charged particle beam device 200 of fig. 2, and charged particle beam device 300 of fig. 3 and 4).

As shown in fig. 1, 1A, 2 to 4, the control unit 700 further includes a database 702. Database 702 is a lookup table that includes information about particles in the form of minerals in a preferred embodiment, database 702 includes characteristics of minerals from real samples originating from different regions of the world. Information about the particles is obtained once and stored in database 702. An example of obtaining such information is shown in fig. 5. A charged particle beam device, such as SEM100 of FIG. 1, is calibrated. Thus, the particular mode of operation of SEM100 is determined. Specifically, the landing energy of the primary electrons impinging on the object 114 is selected (e.g., 15 keV). Furthermore, the first detector 116, the second detector 117, the third detector 121 and the radiation detector 500 are calibrated in method step SA1 by directing a primary electron beam to a known standard calibration object as object 114 and by detecting interacting particles and interacting radiation. The control parameters (such as signal amplification or detector voltage) of the first detector 116, the second detector 117, the third detector 121 and the radiation detector 500 are selected in such a way that an image and a radiation spectrum of a known standard calibration object are obtained in a specific way. After calibration, the properties of the samples in mineral form from different regions of the world are obtained in method step SA 2. In particular, the information includes the gray levels each mineral normally has in the image generated by the interacting particles. Such gray levels may be determined by initially analyzing the particles in SEM100, using interacting particles (such as secondary electrons and/or backscattered electrons) to generate an image. Further, a gray level histogram is generated. A grayscale histogram of an image of a particular particle is a histogram of pixel intensity values of pixels in the image. The histogram includes a count of pixels having a particular gray level intensity. Typically, the histogram shows a high distribution of pixels in the form of peaks. The center of the peak is determined and used as the grey level of this particular particle and stored in the database 702 in method step SA 3. Alternatively, any other method suitable for determining the grey level of a particular particle in a histogram, in particular statistical methods like gaussian models, may be used.

Fig. 6 shows method steps of an embodiment of a method according to the invention for preparing SEM100 for analysis and for preparing an object to be analyzed.

Since the charged particle beam device used for obtaining the information stored in the database 702 may not be exactly the same as the charged particle beam device used for analyzing the unknown object, it is preferred to calibrate the charged particle beam device used for the analysis in method step SB 1. If analysis is performed using SEM100, SEM100 is calibrated. SEM100 is calibrated by selecting the exact same landing energy (i.e., 15keV) for the primary electrons that obtain the above-described characteristics. Furthermore, the first detector 116, the second detector 117, the third detector 121 and the radiation detector 500 are calibrated by directing the primary electron beam to a known standard calibration object as the object 114 and by detecting interacting particles and interacting radiation. The control parameters (such as signal amplification or detector voltage) of the first detector 116, the second detector 117, the third detector 121 and the radiation detector 500 are selected in such a way that an image and a radiation spectrum of a known standard calibration object are obtained in a specific way for obtaining the characteristics.

The object to be analyzed is prepared in method step SB 2. For example, the charged particle beam device 300 of fig. 3 and 4 is used to polish the surface of an object to be analyzed. Furthermore, the object to be analyzed may be coated with a conductive material (such as carbon or metal) to minimize charge accumulation on the surface of the object to be analyzed.

A flow chart of an embodiment of the method is shown in fig. 7. A charged particle beam in the form of a primary electron beam is directed over the object 114 in a method step S1 by using the scanning device 115. In a further method step S2, the interacting particles are detected in the form of backscattered electrons by using the first detector 116 and/or secondary electrons are detected by using the second detector 117. The first detector 116 and the second detector 117 generate first detection signals that may be used to generate an image of the object 114. The generated image 800 of the object 114 is shown in the schematic diagram in fig. 8. The resolution of the image 800 may be less than 100 nm.

An embodiment of the method according to the invention now identifies large particles of particles (e.g. minerals) in method step S3. Large particles are for example larger than 2 μm. Large particles of minerals may have a volume of 2 μm x 2 μm. A first macro particle 801 and a second macro particle 802 are identified in the image 800 (see fig. 8). The compositions of the first large particle 801 and the second large particle 802 can be identified by performing EDX using radiation spectroscopy. A charged particle beam in the form of a primary electron beam can be directed to the center of a first macroparticle 801 and subsequently to a second macroparticle 802. The interaction radiation is detected using a radiation detector 500. As mentioned above, the interacting radiation may be X-rays or cathodo-ray light. In this embodiment of the method according to the invention, X-rays are detected. The radiation detector 500 generates a second detection signal. The radiation spectrum of the first large particle 801 and the radiation spectrum of the second large particle 802 are generated. Each radiation spectrum comprises signal intensity, for example in terms of energy of X-rays. A schematic of such a radiation spectrum is shown in fig. 9. Radiation spectroscopy can be used for EDX. Subsequently, after method step S3 has been performed, the location of large particles in image 800 and their composition are known.

Furthermore, the image 800 is used to identify organic particles in method step S4. For example, organic particles 803 are identified. The organic particles 803 are specified with a given chemical composition, for example, a given chemical composition of 95% by weight carbon and 5% by weight oxygen. This composition of organic materials is very common and accurate. Subsequently, after method step S4 has been performed, the positions of the organic particles in the image 800 and their composition are known.

Furthermore, the image 800 is used to identify pores in method step S5. For example, the aperture 804 is identified. Thus, after method step S5 has been performed, the location of the aperture in the image 800 is known.

Method step S6 now includes directing a beam of charged particles in the form of a primary electron beam over the object 114. The charged particle beam is stopped every 2 μm and the interacting radiation is detected using a radiation detector 500. As mentioned above, the interacting radiation may be X-rays or cathodo-ray light. In this embodiment of the method according to the invention, X-rays are detected. The radiation detector 500 generates a second detection signal. Further, a radiation spectrum is generated using the second detection signal each time the charged particle beam stops. The radiation spectrum includes, for example, signal intensity as a function of X-ray energy. Each radiation spectrum represents a volume element 502 of the object 114, as shown in fig. 10. The volume element 502 has a first extension along a first axis in the form of an x-axis, a second extension along a second axis in the form of a y-axis and a third extension along a third axis in the form of a z-axis. The first axis, the second axis and the third axis may be arranged perpendicular to each other. The first extension, the second extension and/or the third extension may be 2 μm. However, the first extension, the second extension and/or the third extension are not limited to this value. Rather, any suitable value may be selected. The volume element 502 has a volume element surface 503 spanned by a first axis and a second axis.

The image resolution of the image 800 is less than at least one of: a first extension, a second extension, and a third extension. According to one embodiment of the invention the image resolution is 100nm and the first, second and third extensions are 2 μm.

The object 114 as shown in the image 800 comprises several volume elements 502 as schematically shown in fig. 11. The object 114 of the embodiment shown in fig. 11 comprises an array of n x n volume elements 502 facing with their volume element surfaces 503 in the direction of the charged particle beam B. The charged particle beam B impinges on the object 114 substantially perpendicular to the plane of the diagram. The image 800 generated with the interacting particles covers the entire volume element 502.

In method step S7, a region 805 in the image 800 is now selected, for example by a user, since it should be appreciated that this region 805 comprises volume cells 502, each of which may comprise several minerals. One of the volume units 502 is selected and considered. The radiation spectrum of this considered volume element 502 (i.e. the EDX spectrum generated based on the X-rays emitted from the considered volume element 502) may comprise not only information about a single mineral but also information about further surrounding minerals located in the considered volume element 502. Thus, the information provided by EDX spectroscopy may not be understood or may lead to erroneous results. Accordingly, a correction is carried out in method step S8. A flowchart of the correction is shown in fig. 7A.

The radiation spectrum of the volume element 502 under consideration is identified in method step S81. As described above, the radiation spectrum is an EDX spectrum generated based on X-rays emitted from the volume element 502 under consideration. For example, the radiation spectrum reveals information that the volume element 502 under consideration comprises 7% by weight of C, 45% by weight of O, 14% by weight of Si, 5.3% by weight of S, 24% by weight of Ca, and 4.7% by weight of Fe. The goal is to identify the mineral located in the volume of interest unit 502.

An embodiment of the method according to the invention further comprises the step of segmenting the part of the image 800 corresponding to the volume element surface 503 of the considered volume element 502 into color segments (e.g. gray segments) in step S82. The portion of the image 800 generated using interacting particles and having a higher resolution is segmented for the volume element 502 and the volume element surface 503, respectively, in such a way that the portion of the image 800 comprises regions having three color levels, i.e. a first color level, a second color level and a third color level. The first, second and/or third color levels may be gray levels. The grey level is determined by using a grey level histogram of the volume cell surface 503 of the considered volume cell 502. As described above, the gray level histogram of the image 800 of the object 114 is a histogram of pixel intensity values of pixels in the image (i.e., the image generated using interacting particles). The histogram includes a count of pixels having a particular gray level intensity. The histogram shows a high distribution of pixels in the form of peaks. If three peaks are shown in the histogram, the three peaks are identified as a first color level in the form of a first gray level (first peak), a second color level in the form of a second gray level (second peak), and a third color level in the form of a third gray level (third peak). Fig. 12 schematically shows an example of a gray level histogram including three peaks, i.e., a peak P1 at an intensity 128, a peak P2 at an intensity 171, and a peak P3 at an intensity 255. If more than three peaks are shown in the grayscale histogram, only the strongest three peaks are selected.

The segmentation is performed by identifying the beginning and end of peaks P1-P3. This can be done by simply dividing the distance of two adjacent peaks in half or, for example, by using statistical methods such as a gaussian mixture model called GMM. Thus, in the embodiment shown in fig. 12, three sections in the portion of the image 800 referred to as the considered volume unit 502 are generated, namely section I, section II and section III. A portion of an image 800 showing a volume element surface 503 of a considered volume element 502 is shown in fig. 13. Segment I has a first color level (e.g., a first gray level). Segment II has a second color level (e.g., a second gray level) and segment III has a third color level (e.g., a third gray level).

An embodiment of the method according to the invention further comprises the steps of: a first region fraction of the region of the volume element surface 503 comprising the first grey level is determined, a second region fraction of the region of the volume element surface 503 comprising the third grey level is determined, and a third region fraction of the region of the volume element surface 503 comprising the third grey level is determined in method step S83. This may be done by measuring the area fraction using the portion of the image 800 corresponding to the volume unit surface 503. For example, assume that a first region fraction of the region of the volume unit surface 503 comprising the first gray level of segment I is 30% of the area of the volume unit surface 503, a second region fraction of the region of the volume unit surface 503 comprising the second gray level of segment II is 60% of the area of the volume unit surface 503, and a third region fraction of the region of the volume unit surface 503 comprising the third gray level of segment III is 10% of the area of the volume unit surface 503.

An embodiment of the method according to the invention further comprises the steps of: the particles associated with the grey levels are identified in method step S84 by comparing each grey level with the information stored in the database 702. As described above, the database 702 is a look-up table that includes information about ions in mineral form. The information also includes the grey level each particle in mineral form typically has in an image generated using interacting particles. Thus, by comparing the grey levels, possible particles in the form of minerals that can be located in the volume cell 502 under consideration can be identified. Accordingly, a first particle in the form of a first mineral is identified by comparing the first gray level to information stored in the database 702. Similarly, a second particle in a second mineral form is identified by comparing the second gray scale level to information stored in the database 702. Third particles in a third mineral form are identified by comparing the third gray level to information stored in database 702. However, since several minerals differ only slightly from each other, they may have the same grey level in an image generated using interacting particles. Thus, the database 702 may include exactly the same gray levels for different particles in mineral form. If the gray level obtained in the image 800 of the object 114 is associated with several particles in the form of minerals, the database 702 will provide all the minerals associated with this obtained gray level. The user may select a number of minerals for each obtained grey level, which may be located in the volume unit 502 according to the user's assumptions.

For example, method step S84 reveals the following possible minerals:

possible minerals with a first grey level: illite, quartz, and albite (hereinafter referred to as mineral 1).

Possible minerals with a second grey level: biotite, conite, calcite, oolitic chlorite and muscovite (hereinafter referred to as mineral 2).

Possible minerals with a third grey level are rutile, pyrite and blende (hereinafter referred to as mineral 3).

An embodiment of the method according to the invention further comprises the step of determining the composition of the volume element 502 under consideration in method step S85. This step uses information about the identified first particles in the form of mineral 1, the first region score, information about the second particles in the form of mineral 2, the second region score, information about the third particles in the form of mineral 3, and the third region score. The composition of the volume element 502 considered is composed of a first fraction of particles (in the form of mineral 1) in a first region, a second fraction of particles (in the form of mineral 2) in a second region and a third fraction of particles (in the form of mineral 3) in proportion. In other words, the proportion of the first particles in the composition of the volume element 502 under consideration is equal to the proportion of the first region fraction in the entire area of the volume element surface 503. Further, the proportion of the second particles in the composition of the volume element 502 under consideration is equal to the proportion of the second region fraction in the entire area of the volume element surface 503. Further, the proportion of the third particles in the composition of the volume element 502 under consideration is equal to the proportion of the third region fraction in the entire area of the volume element surface 503.

However, mineral 1 may be one of several possible minerals as described above. Furthermore, mineral 2 may be one of several possible minerals as described above. Furthermore, mineral 3 may be one of several possible minerals as described above. Therefore, the following solutions need to be found: composition of

Mineral 1X 0.3

Mineral 2X 0.6

Mineral 3X 0.1

Should equal the composition provided by the radiation spectrum of the volume element 502 under consideration as described above, i.e. the composition

7% by weight of C, 45% by weight of O, 14% by weight of Si, 5.3% by weight of S, 24% by weight of Ca and 4.7% by weight of Fe.

Mineral 1 may be one of the following: illite, quartz, and albite. Thus, mineral 1 is one of 3 minerals.

Mineral 2 may be one of the following: biotite, conite, calcite, oolitic chlorite and muscovite. Thus, mineral 2 is one of 5 minerals.

Mineral 3 may be one of the following: rutile, pyrite, and blende. Thus, mineral 3 is one of 3 minerals.

Thus, 3 × 5 × 3 combinations of minerals are possible (45 combinations), which can provide the composition provided with the radiation spectrum. Accordingly, each of these 45 combinations is now determined by numerical calculation and compared to the composition provided with the radiation spectrum. The determined composition that is closest to the composition provided by the radiation spectrum is selected. The comparing step uses, for example, a least squares method.

For example, one of the 45 possible combinations is the combination of quartz as mineral 1, calcite as mineral 2 and pyrite as mineral 3. The quartz consists of 53.3% by weight of O and 46.7% by weight of Si. Calcite consists of 12% by weight of C, 48% by weight of O and 40% by weight of Ca. Pyrite consisted of 53.4% by weight of S and 46.6% by weight of Fe. Thus, using this determined combination, the volume element 502 under consideration includes a composition

(53.3% by weight of O; 46.7% by weight of Si) x 0.3

(12% by weight of C, 48% by weight of O and 40% by weight of Ca) x 0.6

(53.4% by weight of S and 46.6% by weight of Fe) x 0.1

This results in a determined composition of the considered volume unit 502 based on this combination of 7.2% by weight of C, 44.8% by weight of O, 14% by weight of Si, 5.34% by weight of S, 24% by weight of Ca, 4.7% by weight of Fe. This is very close to the composition provided by the radiation spectrum, as shown in table 1.

Table 1:

the determined composition mentioned in table 1 is selected if it is closest to the composition provided by the radiation spectrum of the total composition based on the possible combinations. Accordingly, the volume element 502 considered comprises 30% quartz, 60% calcite and 10% pyrite.

In a further embodiment of the method according to the invention, a segmentation step is performed for each remaining volume unit 502 of the region 805.

The various embodiments discussed herein may be combined with each other in appropriate combinations with the systems described herein. Further, in some examples, the flow diagrams and/or the order of steps in the described flow processes may be modified as appropriate. Furthermore, various aspects of the systems described herein may be implemented using software, hardware, a combination of software and hardware, and/or other computer-implemented modules or devices having the described features and performing the described functions. The system may further include a display and/or other computer components for providing a suitable interface with a user and/or with other computers.

Software implementations of aspects of the systems described herein may include executable code stored in a computer-readable medium and executed by one or more processors. The computer-readable medium may include volatile memory and/or non-volatile memory, and may include, for example, a computer, a hard drive, ROM, RAM, flash memory, a portable computer storage medium such as a CD-ROM, DVD-ROM, SO card, flash drive, or other drive with, for example, a Universal Serial Bus (USB) interface, and/or any other suitable tangible or non-transitory computer-readable medium or computer memory on which executable code may be stored and executed by a processor. The systems described herein may be used in conjunction with any suitable operating system.

Still other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification and/or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

REFERENCE SIGNS LIST

100 SEM

101 electron source

102 leading out electrode

103 anode

104 beam guide tube

105 first condenser lens

106 second condenser lens

107 objective lens

108 first aperture unit

108A first diaphragm opening

109 second aperture unit

110 pole piece

111 coil

112 single electrode

113 tubular electrode

114 object

115 scanning device

116 first detector

116A reversed field grid

117 second detector

118 second aperture

120 object chamber

121 third detector

122 additional SEM's object Chamber

123 object region

200 charged particle beam device with corrector unit

201 particle beam column

202 electron source

203 leading electrode

204 anode

205 first electrostatic lens

206 second electrostatic lens

207 third electrostatic lens

208 magnetic deflection unit

209 first electrostatic beam deflection unit

209A first multipole cell

209B second multipole cell

210 beam deflection device

211A first magnetic sector

211B second magnetic sector

211C third magnetic sector

211D fourth magnetic sector

211E fifth magnetic sector

211F sixth magnetic sector

211G seventh magnetic sector

213A first mirror electrode

213B second mirror electrode

213C third mirror electrode

214 electrostatic mirror

215 fourth Electrostatic lens

216 second electrostatic beam deflection unit

216A third multipole cell

216B fourth multipole cell

217 third electrostatic beam deflection unit

218 fifth Electrostatic lens

218A fifth multipole cell

218B sixth multipole cell

219 first detector

220 beam guide tube

221 Objective lens

222 magnetic lens

223 sixth electrostatic lens

224 sample stage

225 object

226 object chamber

227 detection beam path

228 second detector

229 scanning device

230 filter electrode

231 analysis unit

232 further magnetic deflection means

300 charged particle beam device

301 first particle beam column

302 second particle beam column

303 object chamber

304 object

305 first optical axis

306 second optical axis

307 second beam generator

308 first electrode

309 second electrode

310 third electrode

311 beam guide tube

312 second particle beam

313 collimator arrangement

314 first toroidal coil

315 deflection coil

316 pinhole diaphragm

317 detector

318 center opening

319 second objective lens

320 magnetic lens

321 electrostatic lens

322 second toroid

323 inner pole piece

324 outer pole piece

325 end

326 terminating electrode

327 grating device

328 object holder

329 first particle Beam

330 first beam generator

331 leading-out electrode

332 collimator

333 iris diaphragm

334 first objective lens

335 grating electrode

500 radiation detector

502 volume unit

503 volume unit surface

504 first volume unit

600 pressure sensor

601 pumping system

602 pressure limiting aperture

700 control unit

701 processor

702 database

800 image

801 first Large particle

802 second Large particle

803 organic particles

804 pores

805 region

B charged particle beam

OA optical axis

OA1 first optical axis

OA2 second optical axis

OA3 third optical axis

Peak P1-P3

Method steps SA1-SA2

Method steps SB1-SB2

Method steps S1-S8

Method steps S81-S85

Claims

1. A method for analyzing an object (114; 225; 304) using a charged particle beam device (100; 200; 300),

-the charged particle beam device (100; 200; 300) comprises a charged particle generator (101; 202; 307; 330) for generating a charged particle beam (312; 329) with charged particles, an objective lens (107; 221; 319; 334) for focusing the charged particle beam (312; 329) onto the object (114; 225; 304), a first detection unit (116, 117; 219, 228; 317) for detecting interacting particles, and a second detection unit (500) for detecting interacting radiation, the interacting particles and the interacting radiation being generated when the charged particle beam impinges on the object (114; 225; 304) and comprising a database (702) storing information on characteristics of first and second particles,

wherein the method comprises the steps of:

-directing the charged particle beam over the object (114; 225; 304);

-detecting the interacting particles using the first detection unit (116, 117; 219, 228; 317), generating a first detection signal using the first detection unit (116, 117; 219, 228; 317), and generating an image (800) of the object (114; 225; 304) using the first detection signal, the image (800) comprising regions (I, II, III) with different color levels, and the image (800) having an image resolution;

-detecting the interaction radiation using the second detection unit (500), generating a second detection signal using the second detection unit (500), and generating a radiation spectrum using the second detection signal, the radiation spectrum representing a volume element (502) of the object (114; 225; 304) and providing information about an overall material composition of the volume element (502), the volume element (502) having a first extension along a first axis (x), a second extension along a second axis (y), and a third extension along a third axis (z), the image resolution being smaller than at least one of: the first extension, the second extension, and the third extension, and the volume element (502) has a volume element surface (503) that is spanned by two of: the first axis (x), the second axis (y) and the third axis (z);

-segmenting a portion of the image (800) corresponding to the volume unit surface (503) into regions having a first color level and a second color level;

-determining a first region score of the region comprising the first color level, and determining a second region score of the region comprising the second color level;

-identifying the first particles associated with the first color class by comparing the first color class with the information stored in the database (702), and identifying the second particles associated with the second color class by comparing the second color class with the information stored in the database (702); and

-determining a composition of the volume unit (502) by using the characteristics of the first particles, the first region fraction, the characteristics of the second particles and the second region fraction, wherein the composition of the volume unit (502) consists of the first particles in an amount of the first region fraction in proportion to the second particles in an amount of the second region fraction.

2. The method of claim 1, wherein at least one of the first color level and the second color level is a gray scale level.

3. The method of claim 1 or 2, wherein at least one of the first particles and the second particles is a mineral.

4. The method of claim 1, wherein,

-the database (702) further stores information on characteristics of third particles, and

-the region further comprises a third color level, and wherein,

the method further comprises:

-determining a third region score of the region comprising the third color level;

-identifying the third particles associated with the third color level by comparing the third color level with the information stored in the database (702); and

-determining the composition of the volume element (502) also by using the third particles and the third region fraction, wherein the composition of the volume element (502) also proportionally consists of the third particles in an amount of the third region fraction.

5. The method of claim 4, wherein the region includes only the first, second, and third color levels.

6. The method of claim 4 or 5, wherein the third color level is a gray level.

7. The method of any one of claims 1, 2, 4 or 5, wherein the database (702) comprises information on characteristics of a plurality of first particles and on characteristics of a plurality of second particles, wherein the method comprises at least one of the following features:

(i) the step of identifying the first particle further comprises: identifying a portion or all of the plurality of first particles associated with the first color level;

determining a single first particle from the portion or all of the plurality of first particles associated with the first color level, wherein a characteristic of the single first particle is closest to the information about the overall material composition of the volume element (502) relative to all of the plurality of first particles, an

The step of determining the composition of the volume unit (502) comprises: using the single first particle;

(ii) the step of identifying the second particle further comprises: identifying a portion or all of the plurality of second particles associated with the second color level;

determining a single second particle from the portion or all of the plurality of second particles associated with the second color level, wherein a characteristic of the single second particle is closest to the information about the overall material composition relative to all of the plurality of second particles, an

The step of determining the composition of the volume element (502) comprises using the single second particle.

8. The method of any of claims 1, 2, 4 or 5, wherein the step of segmenting the portion of the image (800) comprises using a grayscale histogram.

9. The method of any one of claims 1, 2, 4 or 5, wherein the method further comprises at least one of the following steps:

-if the first particle is larger than the volume element (502), identifying the first particle by using the radiation spectrum;

-if the second particle is larger than the volume element (502), identifying the second particle by using the radiation spectrum;

-specifying a given chemical composition for the organic material if the volume element (502) comprises the organic material.

10. The method of claim 9, wherein

-assigning to the organic material a given chemical composition having 95% by weight of carbon and 5% by weight of oxygen.

11. The method of any of claims 1, 2, 4, or 5, comprising at least one of the following features:

-the interacting particles are secondary particles;

-the interacting particles are secondary electrons;

-the interacting particles are backscatter particles;

-the interacting particles are backscattered electrons;

-the interaction radiation is X-ray radiation; and

-said interacting radiation is cathodo-ray light.

12. The method of any of claims 1, 2, 4, or 5, comprising:

-calibrating at least one of the first detection unit (116, 117; 219, 228; 317) and the second detection unit (500) using a calibration object.

13. A method for analyzing an object (114; 225; 304) using a charged particle beam device (100; 200; 300),

-the charged particle beam device (100; 200; 300) comprises a charged particle generator (101; 202; 307; 330) for generating a charged particle beam (312; 329) with charged particles, an objective lens (107; 221; 319; 334) for focusing the charged particle beam (312; 329) onto the object (114; 225; 304), a first detection unit (116, 117; 219, 228; 317) for detecting interacting particles, and a second detection unit (500) for detecting interacting radiation, the interacting particles and the interacting radiation being generated when the charged particle beam impinges on the object (114; 225; 304) and comprising a database (702) storing information on characteristics of a plurality of particles,

wherein the method comprises the steps of:

-directing the charged particle beam over the object (114; 225; 304);

-identifying a first portion of the plurality of particles by comparing the first color level with the information stored in the database (702), and identifying a second portion of the plurality of particles by comparing the second color level with the information stored in the database (702), the first portion being associated with the first color level, the second portion being associated with the second color level,

-determining a possible composition of the volume unit (502) for each possible combination of the individual particles of the first part of the plurality of particles and the individual particles of the second part of the plurality of particles by using the characteristics of each individual particle of the first part of the plurality of particles, the first region fraction, the characteristics of each individual particle of the second part of the plurality of particles and the second region fraction, wherein the composition of the volume unit (502) consists of the individual particles of the first part of the plurality of particles in an amount of the first region fraction in proportion to the individual particles of the second part of the plurality of particles in an amount of the second region fraction,

-comparing each possible composition of the volume element (502) with the overall material composition of the volume element (502) provided by the radiation spectrum, and

-determining an actual composition of the volume element (502) by selecting the composition that is closest to the overall material composition of the volume element (502) provided by the radiation spectrum from all possible compositions of the volume element (502).

14. The method of claim 13, wherein at least one of the first color level and the second color level is a gray scale level.

15. The method of claim 13 or 14, wherein the particles of the plurality of particles are minerals.

16. The method of claim 13 or 14,

-the region further comprises a third color level, and wherein,

the method further comprises:

-identifying a third portion of the plurality of particles by comparing the third color level with the information stored in the database (702), the third portion being associated with the third color level,

wherein the content of the first and second substances,

the step of determining a possible composition of the volume element (502) also takes into account each possible combination with each individual particle of the third portion of the plurality of particles by using the characteristics of the individual particles of the third portion of the plurality of particles and the third region fraction.

17. The method of claim 16, wherein the region includes only the first, second, and third color levels.

18. The method of claim 16, wherein the third color level is a gray scale level.

19. The method of any of claims 13, 14 or 17, wherein the step of segmenting the portion of the image (800) comprises using a grayscale histogram.

20. The method according to any one of claims 13, 14 or 17, wherein the method further comprises at least one of the following steps:

-if the volume element (502) comprises only one particle and if the one particle is larger than the volume element (502), identifying the one particle by using the radiation spectrum;

21. The method of claim 20, wherein

22. The method according to any one of claims 13, 14 or 17, comprising at least one of the following features:

-the interacting particles are secondary particles;

-the interacting particles are secondary electrons;

-the interacting particles are backscatter particles;

-the interacting particles are backscattered electrons;

-the interaction radiation is X-ray radiation; and

-said interacting radiation is cathodo-ray light.

23. The method of any of claims 13, 14 or 17, comprising:

24. A computer readable medium, having stored thereon a computer program product comprising program code which is loaded into a processor (701) and which, when executed, controls the charged particle beam device (100; 200; 300) in such a way that the method according to any of claims 1-23 is performed.

25. A charged particle beam device (100; 200; 300) for analyzing an object (114; 225; 304), the charged particle beam device comprising:

a charged particle generator (101; 202; 307; 330) for generating a charged particle beam having charged particles,

an objective lens (107; 221; 319; 334) for focusing the charged particle beam (312; 329) onto the object (114; 225; 304),

-a first detection unit (116, 117; 219, 228; 317) for detecting the interacting particles; and a second detection unit (500) for detecting interacting radiation, the interacting particles and the interacting radiation being generated when the charged particle beam impinges on the object (114; 225; 304),

-a database (702) storing information about characteristics of particles, and

-a processor (701) into which the computer program product according to claim 24 is loaded.

26. Charged particle beam device (100; 200; 300) according to claim 25, further comprising one of the following features:

-the first detector comprises said first detection unit (116, 117; 219, 228; 317) and the second detector comprises said second detection unit (500); and

-a single detector comprises said first detection unit (116, 117; 219, 228; 317) and said second detection unit (500).

27. Charged particle beam device (200) according to claim 25 or 26, wherein the charged particle generator is a first charged particle beam generator (330) for generating a first charged particle beam having first charged particles, wherein the objective lens (334) is a first objective lens for focusing the first charged particle beam onto the object (304), and wherein the charged particle beam device (200) further comprises: a second charged particle beam generator (307) for generating a second charged particle beam (312) having second charged particles and a second objective lens (319) for focusing the second charged particle beam (312) onto the object (304).

28. Charged particle beam device (100; 200; 300) according to claim 25 or 26, wherein the charged particle beam device (100; 200; 300) is at least one of: an electron beam device and an ion beam device.